Eyewear is believed to have been developed in Europe and China during the thirteenth century. It is also believed that primitive man used shields made from bone and/or wood to protect their eyes from sun and wind. Primarily, eyewear was developed for functional reasons, namely to improve the wearer's vision and to protect their eyes from environmental elements. As time passed, eyewear as a fashion accessory became common.
Eyewear has many basic components and generally accepted terminology. Frames, primarily made of plastic, metal, or the like, are provided for holding lenses positionable in close proximity to the eyes of the wearer. A bridge, which is typically integral with the frame, typically rests on the wearer's nose and provides a natural resting spot for the frame. A hinge may be mounted to the frames at each side and temples, which are proximal the wearer's head, extend from the other side of each hinge. Earpieces may extend downwardly from the temples near the wearer's ears to further secure the eyewear.
The frame, which holds the lenses that correct or otherwise alter the wearer's vision, includes a frame front. The two temples may be replaced with a single strap that goes around the head such as used in goggles. New advances in materials, memory metals in particular, permit the replacement of a traditional hinge with a continuous structure and suggest that the term “joint” may be used instead of hinge. Indeed, the term “joint” may also be more appropriate for eyeglasses employing a strap instead of temples. The frames provide a frame cavity, which may also be referred to as an aperture, to carry a lens. The left lens is typically referred to as ocular sinister (OS) and the right lens is typically referred to as ocular dexter (OD).
Frames generally fall into one of three categories: rimmed, semi-rimless, and rimless. In a rimmed configuration, the lens aperture is completely encircled by the frame. In a semi-rimless configuration, a partial frame carries the lens, although the frame may include a filament which functions to hold the lens in place without providing the appearance of a rim. And in a rimless configuration, the lenses are directly carried by the temples and/or bridge so that no frame encircles the lens or lenses.
The hinges between the temples and the frames may be provided in a number of different constructions. The standard friction hinge is a discrete hinge that attaches the temples and frame front to one another. A spring hinge may also be provided wherein a spring is utilized to bias the connection between the temples and frame front so as to provide a more secure or snug fit on the head of the person wearing the eyewear. An integrated hinge utilizes fingers, or leafs, which are an extension of the respective temples and frame front and wherein a hinge pin is added to connect the fingers and leafs to one another. As mentioned previously, a continuous hinge may be provided wherein the frame front and temples are continuous or integral with one another.
Prior art eyewear utilizes frame rims which are elastically distorted to permit a rigid lens, provided with or without a beveled edge, to be inserted into the frame aperture. Plastic frames are often heated to increase the elasticity of a material so as to allow for the distortion which is relatively small. Metal frames may also be used and often have mechanical joints that are opened to accommodate the rigid lens. It will be appreciated that large deformations are possible with metal frames so as to allow for insertion of appropriate sized lenses.
Electro-optical materials, which change their optical appearance upon application of an electrical field, have been developed for use with eyewear. Liquid crystal materials are commonly used but other electro-optic materials show promise. These materials can be used in eyewear such as goggles and visors, it will be appreciated that a number of problems are realized in attempting to incorporate a liquid crystal device into a prior art eyewear frame. Indeed, given the basic form and construction of a liquid crystal device or any device which uses an electro-optic material that can be used in a lens, special features must be incorporated into an eyeglass frame to accommodate such a lens. As will be understood by a skilled artisan, liquid crystal and other electro-optic lenses have an edge seal wherein a glue or adhesive bead with different electro-optical properties than the active area—the area containing the electro-optic material—is provided. It will be appreciated that it is desirable to hide the edge seal within the eyewear frame. Moreover, these types of lenses require protruding tabs to serve as electrodes for allowing application of a desired electrical waveform or voltage to the electro-optic material. Accordingly, the device, the edge seal, and/or the electrode tabs are typically not robust enough to survive insertion into an elastically deformed frame. This is especially true in sunglasses which do not employ a carrier lens. In other words, in generally ophthalmic eyewear applications, a corrective lens is provided which provides a substantial carrier or base to which the liquid crystal device may be attached. As such, the rigidity of the carrier is able to withstand the forces required to insert the lens into the eyewear. However, a liquid crystal lens or similar lens, by itself, cannot withstand such forces. It will further be appreciated that the electro-optic lenses require batteries, drive circuits, switches and other interconnecting conductors for operation. These components must be located somewhere in or on the frame while maintaining an aesthetically pleasing appearance or indeed, be totally unobservable by the wearer or the casual observer.
One aspect of liquid crystal lenses that have proven to be problematic is the interface of the liquid crystal (LC) lens electrodes which are used to apply an electric field to the liquid crystal material. Past LC lenses required each electrode to be patterned with a special tab to which some type of conductor, e.g. wire or tape, was used for interconnection to a control circuit. Although such an approach was workable, it has been found to be difficult to implement for manufacturing a large number of lenses. And such an interconnection was found to be somewhat unreliable and susceptible to breakage. Moreover, the need to form a tab hinders the ability to extend the electro-optically active material to peripheral edges of the lens. Additionally, some lens designs have used small amounts of conductive materials (adhesives) as so-called “crossover dots” to electrically connect the electrode of one substrate to a separate conductive tab on the opposing substrate. As such, crossover dots further complicate lens design and provide another point for device failure. A further drawback of lens designs employing crossover dots is that if the lens is found to be defective, the lens cannot be easily repaired.
Based upon the foregoing problems, it will be appreciated that there is a need for an improved interconnection of electro-optic lenses. Indeed, there is a need for lens interconnections that do not require special patterning of the electrode layers on the lenses. And there is a need for an interconnection that is flexible and robust.